Both the 3-Button Windlass Remote Kit and the 5-Button Windlass & Thruster Kit are easily retrofitted to existing installations and include a replaceable battery. The fobs float and are waterproof to IP67 (1 Meter deep). Using over one billion individual codes, our proprietry encryption scheme prevents false triggering from any other device or similar fob. And both kits include a Receiver that supports up to eight remote key fobs (additional fobs sold separately).